RE: patent 1475980:
The patent was assigned to the Alemite Mfg. Co. of Chicago, which was subsequently acquired by Bassick (a company that made metal creeper wheels) and later on acquired by SKF, a multi-national corporation headquartered in Sweden.
Decades of mergers, acquisitions, and name changes makes the picture look confusing, but it looks like your grease gun was made no later than 1940, and quite possibly earlier based on the way the handle is marked.
(Somebody give me a second opinion on that please - I'm thinking no later than 1928. BK)
Alemite / Alemite Die Casting Co., Chicago, IL / lubrication division acquired 1919 by Bassick Co., Chicago, IL /
Alemite / Alemite LLC, St. Louis, MO / est. 1918 / tool storage systems, work benches, merchandisers /
https://www.servicemerchandisers.com/alemite /
https://www.skf.com/alemite/about/the-alemite-story /
https://www.garagejournal.com/forum/threads/alemite-zerk-bassick-hand-held-grease-guns.553024/ /
Alemite / Alemite Lubrication Co., Chicago, IL / est. 1918, acquired 1919 by Bassick Mfg. Co. /
https://www.garagejournal.com/forum/threads/alemite-zerk-bassick-hand-held-grease-guns.553024/ /
Alemite / Alemite Mfg., Chicago, IL / acquired 1919 by Bassick Co., Chicago, IL, renamed Alemite Mfg. Co. 1928, renamed Alemite Corp. 1931 / patent 1475980 Dec 4 1923 Oscar Zerk / /
https://www.garagejournal.com/forum/threads/alemite-zerk-bassick-hand-held-grease-guns.553024/ /
Alemite / Alemite SKF, Sven Wingquists Gata 2, SE-415 50, Gothenburg, Sweden /
https://www.skf.com/alemite/ /
https://www.garagejournal.com/forum/threads/alemite-zerk-bassick-hand-held-grease-guns.553024/ /
==
Bassick / Bassick Alemite Corp., Chicago, IL / inc. Feb 1923, acquired Nov 1924 by Stewart Warner Corp. /
https://www.garagejournal.com/forum/threads/alemite-zerk-bassick-hand-held-grease-guns.553024/ /
Bassick / Bassick Co., 275 Warren St., Bridgeport, CT / est. 1879 (as Samuel A. Burns Co.), inc. May 1917, merged with M. B. Schenck Company and Universal Caster & Foundry Co. 1917, acquired 1923 by Stewart Warner Corp., Chicago, IL /
https://www.garagejournal.com/forum/threads/alemite-zerk-bassick-hand-held-grease-guns.553024/ /
https://mycompanies.fandom.com/wiki/Bassick_Company /
Bassick / Bassick Mfg. Co., 2660 N. Crawford Ave., Chicago, IL / est. 1919 acquired Alemite Lubrication Co. and renamed Bassick Alemite Corp. Dec 1919, renamed Alemite Mfg. Co. 1928 / grease gun / patent 1475980 Dec 4 1923 Oscar Zerk /
https://www.garagejournal.com/forum/threads/alemite-zerk-bassick-hand-held-grease-guns.553024/ /
==
SKF / SKF Sweden AB, Sven Wingquist Gata 2, 415 50 Goteborg, Sweden /
https://www.skf.com/se / est. 1907 / see also SKF USA Inc., Lansdale, PA /

patent 1475980 May 21 1923 Oscar Zerk